SITUATION
The "Service Engine Soon" (MIL) lamp is illuminated and a power reduction is clearly perceptible. This situation may occur after driving for some time with the engine already at full operating temperature. If the ignition is cycled, the engine then usually performs normally.

CAUSE
The VANOS fault is usually caused by an insufficient oil pressure supply to the inlet VANOS adjustment unit.

To effectively move the camshafts to the target positions, in the specified time and under all engine conditions, sufficient oil pressure supply to the VANOS control pistons must always be available.

When the engine operation requires that VANOS quickly advance the intake camshaft, fault 2A82 may be set if the intake camshaft is "late", or does not reach the target position. In this situation, engine power may be reduced and a check control message displayed. The consequential fault 3100 can also be set in the DME fault memory as well.

If this fault is stored under these conditions, the possible cause is that the camshaft hook ring seals (3) have worn a groove into the camshaft bearing ledge (1), causing a drop in oil supply to the VANOS unit.

If excessive wear to the camshaft bearing ledge is found, it is only necessary to replace the intake camshaft sealing rings and the intake camshaft bearing ledge.

PARTS INFORMATION
Part Number
Description
Quantity

11 31 1 705 512
Intake camshaft hook ring seals
2

11 12 7 550 913
Intake bearing ledge
1

WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.

Defect Code
11 31 21 26 00

Main Work*

Labor Operation:
11 31 028
Removing and installing or replacing

Labor Allowance:
Refer to KSD

*Main Work:
Use this labor operation number when this is the only repair being performed, or if this is the main repair when performed along with other repairs at the same time. If this is not the main repair, refer to KSD for the associated (+) labor operation code.